spf1.lnmailer.net has no CNAME records.
Question and response
Question
dig spf1.lnmailer.net. NS
Answer
The response has no answer records.
Authority
lnmailer.net. 1423 SOA ns1.viidakko.fi. admin.dnsimple.com. 1727957529 86400 7200 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0